Jan 6 (Reuters) - The efficacy of boosters against COVID-19 is likely to decline over the next few months and people may need another shot in the fall of 2022, Moderna Inc (MRNA.O) Chief Executive Officer Stephane Bancel said at a Goldman Sachs-organized healthcare conference on Thursday. Bancel said the company is working on a vaccine candidate tailored to the Omicron variant of the coronavirus, but is unlikely to be available in the next two months. "I still believe we"re going to need boosters in the fall of "22 and forward," Bancel said. His comments on needing a fourth shot come on the back of Israeli Prime Minister Naftali Bennett citing a study on Tuesday that a fourth dose of COVID-19 vaccine boosts antibodies five-fold a week after the shot is administered. Moderna, which benefits by repeat inoculations, during its third quarter earnings results said commercial booster market sales could be up to $2 billion in the United States in 2022.